1. Field of the Invention
The invention relates to a damping element for a catching device for preventing a person from falling from a ladder, a landing or similar, the person being secured by a catching belt on the catching device. The damping element is oblong and has a non-rectilinear shape. In the event of a fall, the damping element is deformed by the fall energy into a more linear shape, as a result of which the catching impact is damped.
2. Description of the Prior Art
Such catching devices can have a carriage which can be guided along the guide rail as well as a fastening device for securing the catching belt to the carriage, the fastening device containing the damping element which damps the catching impact in the event of a fall. Such a catching device is known where the fastening device has an S-shape for forming the damping element. Because of the loads and forces which are exerted on the damping element during the normal use of such a catching device, there is the danger that in the course of time the damping element deforms from its original S-shape into a more elongated shape so that the damping function is impaired.
From DE-A-34 26 551, a catching device for a climbing guard system is known where the fastening device is a somewhat reniform dented steel ring which is elongated in the event of a fall. The fall energy is reduced by the elongation and as a result the catching impact is damped.
From DE-A-26 37 593, a damping device for a safety harness is known which contains a section folded several times in a zigzag shape which likewise absorbs a part of the fall energy in the event of a fall and thus damps the catching impact.
A carriage or a runner with a damping element is furthermore known from DE-U-295 01 716. The damping element rests on a pin-shaped projection of a pawl and a crosspiece is housed on the pin-shaped projection between the damping element and the carriage. For this catching device, the damping path is limited or an enlargement of the damping path would inevitably lead to an unmanageable size of the catching device.
The object of the invention is to create a damping element for a catching device where a deformation or an impairment of the damping function by the forces and loads normally occurring during use is avoided.
According to the invention this object is achieved in that the damping element is fixed in its non-rectilinear shape, the fixing being so dimensioned that it releases the damping element when a certain load is applied, so that this can damp the catching impact.
The non-rectilinear shape of the damping element can mean that the damping element has a S or U-shape, is spiral or rolled up or is curved or is bent in some other way so that it can be brought out of this non-rectilinear shape into a linear or elongated shape only by application of force.
Fixing is preferably by means of links, welding points, rivets, bands or brackets, which are positioned so that there is as large as possible a distance between them and the bending or other curvature of the non-rectilinear shape effected by the S-fold.
The catching device according to the invention can be of the type known from DE-U-295 01 761 where a pawl is rotatably housed in the carriage which runs up against catching stops in the guide rail in the event of a fall and in which the catching belt is secured to the pawl. Instead of the pawl, an arrestor lever can also be provided which presses against the rail in the event of a fall and stops the carriage on the rail by friction.
For rails which run horizontally, pawls or arrestor levers are not used in general and the fastening device can consist of a lug or a connector articulated to the carriage.
The damping element preferably consists of a flat steel bar folded or rolled-up one or more times. The intensity of the catching impact can be limited by the dimensioning of the flat steel bar. In the event of a fall, a maximum of 6 kN should act on the person. To limit the catching impact to approx 4 kN, the flat steel bar has a cross-section of 8xc3x9710.5 mmxe2x80x94material steel 1.4301. The links for fixing the form of the damping element can have a cross-section of 0.5xc3x978 mm.
While the links or welding points are form-fixing means, which are nonreleasably connected to the damping element, fixing means in the form of bands or brackets need not be nonreleasably connected to the damping element. These form-fixing means are closed in themselves, but need not be nonreleasably connected to the damping element.
In order to prevent a person from being injured by the remains of links in the event of a fall, the area immediately surrounding the links is recessed, the recess optionally being able to be surrounded by a raised edge. The areas of the damping element folded onto each other can therefore touch each other in the area of the links so that the remains of the links are very short and do not project beyond the contour of the damping element. Another possibility is to provide covering plates overlapping laterally at the links, which cover remains of links.